Add replace_last and remove_last filters

History.md

@@ -3,6 +3,7 @@
 ## 5.1.0 / 2021-09-09
 
 ### Features
+* Add `remove_last`, and `replace_last` filters (#1422) [Anders Hagbard]
 * Add `base64_encode`, `base64_decode`, `base64_url_safe_encode`, and `base64_url_safe_decode` filters (#1450) [Daniel Insley]
 * Introduce `to_liquid_value` in `Liquid::Drop` (#1441) [Michael Go]
 

lib/liquid/standardfilters.rb

@@ -296,14 +296,24 @@ def replace_first(input, string, replacement = '')
       input.to_s.sub(string.to_s, replacement.to_s)
     end
 
+    # Replace the last occurrences of a string with another
+    def replace_last(input, string, replacement)
+      input.to_s.sub(/.*\K#{Regexp.escape(string.to_s)}/, replacement.to_s)
+    end
+
     # remove a substring
     def remove(input, string)
-      input.to_s.gsub(string.to_s, '')
+      replace(input.to_s, string, '')
     end
 
     # remove the first occurrences of a substring
     def remove_first(input, string)
-      input.to_s.sub(string.to_s, '')
+      replace_first(input.to_s, string, '')
+    end
+
+    # remove the last occurences of a substring
+    def remove_last(input, string)
+      replace_last(input.to_s, string, '')
     end
 
     # add one string to another

test/integration/standard_filter_test.rb

@@ -539,19 +539,39 @@ def test_first_last
   end
 
   def test_replace
-    assert_equal('2 2 2 2', @filters.replace('1 1 1 1', '1', 2))
+    assert_equal('b b b b', @filters.replace('a a a a', 'a', 'b'))
     assert_equal('2 2 2 2', @filters.replace('1 1 1 1', 1, 2))
-    assert_equal('2 1 1 1', @filters.replace_first('1 1 1 1', '1', 2))
+    assert_equal('1 1 1 1', @filters.replace('1 1 1 1', 2, 3))
+    assert_equal('b a a a', @filters.replace_first('a a a a', 'a', 'b'))
     assert_equal('2 1 1 1', @filters.replace_first('1 1 1 1', 1, 2))
-    assert_template_result('2 1 1 1', "{{ '1 1 1 1' | replace_first: '1', 2 }}")
+    assert_equal('1 1 1 1', @filters.replace_first('1 1 1 1', 2, 3))
+    assert_equal('a a a b', @filters.replace_last('a a a a', 'a', 'b'))
+    assert_equal('1 1 1 2', @filters.replace_last('1 1 1 1', 1, 2))
+    assert_equal('1 1 1 1', @filters.replace_last('1 1 1 1', 2, 3))
+    assert_template_result('b b b b', "{{ 'a a a a' | replace: 'a', 'b' }}")
+    assert_template_result('2 2 2 2', "{{ '1 1 1 1' | replace: 1, 2 }}")
+    assert_template_result('1 1 1 1', "{{ '1 1 1 1' | replace: 2, 3 }}")
+    assert_template_result('b a a a', "{{ 'a a a a' | replace_first: 'a', 'b' }}")
+    assert_template_result('2 1 1 1', "{{ '1 1 1 1' | replace_first: 1, 2 }}")
+    assert_template_result('a a a a', "{{ 'a a a a' | replace_first: 'b', 'c' }}")
+    assert_template_result('a a a b', "{{ 'a a a a' | replace_last: 'a', 'b' }}")
+    assert_template_result('1 1 1 2', "{{ '1 1 1 1' | replace_last: 1, 2 }}")
+    assert_template_result('a a a a', "{{ 'a a a a' | replace_last: 'b', 'c' }}")
   end
 
   def test_remove
     assert_equal('   ', @filters.remove("a a a a", 'a'))
     assert_equal('   ', @filters.remove("1 1 1 1", 1))
-    assert_equal('a a a', @filters.remove_first("a a a a", 'a '))
+    assert_equal('b a a', @filters.remove_first("a b a a", 'a '))
     assert_equal(' 1 1 1', @filters.remove_first("1 1 1 1", 1))
-    assert_template_result('a a a', "{{ 'a a a a' | remove_first: 'a ' }}")
+    assert_equal('a a b', @filters.remove_last("a a b a", ' a'))
+    assert_equal('1 1 1 ', @filters.remove_last("1 1 1 1", 1))
+    assert_template_result('   ', "{{ 'a a a a' | remove: 'a' }}")
+    assert_template_result('   ', "{{ '1 1 1 1' | remove: 1 }}")
+    assert_template_result('b a a', "{{ 'a b a a' | remove_first: 'a ' }}")
+    assert_template_result(' 1 1 1', "{{ '1 1 1 1' | remove_first: 1 }}")
+    assert_template_result('a a b', "{{ 'a a b a' | remove_last: ' a' }}")
+    assert_template_result('1 1 1 ', "{{ '1 1 1 1' | remove_last: 1 }}")
   end
 
   def test_pipes_in_string_arguments
@@ -853,16 +873,20 @@ def test_all_filters_never_raise_non_liquid_exception
       ["foo", 123, nil, true, false, Drop, ["foo"], { foo: "bar" }],
     ]
     test_types.each do |first|
-      test_types.each do |other|
-        (@filters.methods - Object.methods).each do |method|
-          arg_count = @filters.method(method).arity
-          arg_count *= -1 if arg_count < 0
-          inputs = [first]
-          inputs << ([other] * (arg_count - 1)) if arg_count > 1
-          begin
-            @filters.send(method, *inputs)
-          rescue Liquid::ArgumentError, Liquid::ZeroDivisionError
-            nil
+      test_types.each do |second|
+        test_types.each do |third|
+          (@filters.methods - Object.methods).each do |method|
+            arg_count = @filters.method(method).arity
+            arg_count *= -1 if arg_count < 0
+            inputs = [first]
+            inputs << ([second] * (arg_count - 1)) if arg_count > 1
+            inputs << ([third] * (arg_count - 1)) if arg_count > 2
+
+            begin
+              @filters.send(method, *inputs)
+            rescue Liquid::ArgumentError, Liquid::ZeroDivisionError
+              nil
+            end
           end
         end
       end